Radio signaling system



IN VEN TOR.

ATTORNEY July'lo, 1923.

' H. A; AFF-El.

RADIO SIGNALING .SYSTEM Fned Aug 31, 1922 T l l 1.-

Frequemvy i@ fw BY. MW

July 10,1928. 1,676,240

' H. A. AFFEL vmmm SIGNALING SYSTEM l Filed Aug. :51. 1922 2Sheets-Sheet 2 V INVENTOR.

fx@ l WTTQRNEY A i' l 15v i'sfdiselosed inthe patent to Latour j fSeptemher21gl920. .In

20 and in all the: prior f beingsneh'as to afford A i Patented July 1o,1928;'

f nnnimne;

loading and terminating antenna strn'otiies in 'order to minimize 5toincrease` thereiiieienoy of such'strnetures.V

As is' Well l'mov'vn'fto 'those itamiliar with the art, various typesVof structures have been pr'oposedn snlostanti'ally' all 'of whichhavehad in vivewfitlieeobjectk 'eitherofti1ning frequency eroi mit Lmoree'tlieientlyaa partieularfhand of frequencies. An arrangementAadafptedfto at-1 tain the irst of the above' mentioned objects ithe`antenna for a particular dated September 23, 19'19", An 'arrangementfor attaining the second "o'h'jec'tisl disolosed' in the'patentto'Espensohied lgfdatedf both' of rthese patents art known to me', thein dnet'anee with which the lalnt'ennais loaded has-heen distrilontfedvyuniformly "or at uniform intervals' throughout the .length 'of the f'antenna.A It isio'ne of'tlieolojeets ofA my inven-y tion to provide a'tapered loaded antenna 'in' vvhfie-h the'inductanc'eis ly`, or ineffect', at unequal intervals. through-p out'the length of the antznria,`

Another ohjeet'otmy S5 the surge impedanceof the 'antennas'truol Thisresnltsfinthe [diminution of .re-. eetion losses' @in an Vantenna of,this j type. A further object Aolf inventionweonsists -in combining ataperedloaded. antenna hayture.

"40d ing a broad' band characteristic vvitha' plurality of receivingeireuitssojas'to provide for multiplex operation` thefeonn'e'ction`hetween the antenna 'and v the receiving circuits minimumjinipedanceto' allffrequencies exeept those intended tor `thepartieularreceivingcircuit@` i Other objects. of this invention lWill be apparentfrom thelfollowing description t when read in eonneetioa-lwith thejatt-acheel thelosses and" the i."efore` loaded `antenna'I making. itv adaptedfto"trans- Whieh simulates 'electrically' i ,Arran elefnoennrm; YORK4Aeste,neR, manners wegnemen@ reeeemraroomrenwe CORPOMTIQN erfNnW ons eFiei're .e Y. loaded-"ant nna in which'ednalf'induetanees drawing ofwhich 1 tervals 'apart l the direetion tovvardl the shows heiinpedane'e-freqenoy 'feharaetleri' istie' :of the iilter arrangen'ient'shown in ".lpiglfk 1 Fig. '2 j shoWs antenna? oi' "similar 'type'V inwhich unequal' 'indnetanees are' sp'aoed "at" equ'alint'erv i the openendf'of `the*`antennaf;" Figi' 3; shows the combination with i tenna,suoli as isshovvn infliglgof mnatng 'neteferklfeaeel eje' 'elle .Serafii). ance of theantennafstrnetre ;:.Figg .f4* sho vs a. similarVnetvvorlij 'adaptedf'ftor oonnectio y vs'lith'the antenna show ninFigQfshows" a loopfanten'na off.' the'tapered ltjafcleA u type terminatedhyjan impedance .as in F and'e'; Figg' i tenna t'erminate'd'hy yaniinpeda 'er which antennainayfhe' loadedin the mann l shown in Figs. f1'and 25' Eig'. 7 shows. a;k `lt r1gfli'ori zontal 'antennaf i iterminatedfas shovvn-fin thef'pre'o'edin gf ureS,' amr wei-Caine. a'piume-@55 ef; reeelfviiea stead 'of lin series; as shown in E l'gs. ncl2; .Fig.57' shofv'vstheV4 impedantieeharaete'ristie 'offthe ilterQa-rrafno4 sho'vvn'in Fig,YgandFigf8shov7sas arrangement 'of' terminaloireuitfs4 j tor aA leopantenna;circuit.'` 1" In Fig.; 1,11?" L typte,Whieh'is'ygrounded at; what-maybe termed 'its lfnear. end through'aplurality bend ltere F-J'Fa fFt; 'The antenne; lilies. connectedtherewitltfa'pliirality 'offirinhi'c-l weefsels e, e ef 'theeememegetedelf'Tbe l. which are shown` by dotted linesa'ndv d 1' '7 cated QKA .are 'intended 'to repr'esenti fth'eg vj capacity ofthe antennategronndg"TheQ1ni duotanees 2, 3, et and '5 :are-spaoed at progres#sive'ly'l deer'easingf' distances apart in'. the d-ireetionfrornthenearend of the 'antenna to- 95 wardjthe'dietaneendg* Thespacngfqftheseindnetanoes shonld'preterably i' aree with, e eeereasiea feeapagan@ wenn f feng :tapered 56.- j

circuits Connected-therewith@in para el,

aegee ich arei'preferably'-,

ioneensersfz, l i

characteristics, looking 4is uniformly distributed throughout its lengthassuming uniform separation), the combination of an inductance with theshunt capacity forms af series of networks of increasing impedance inthe direction from the Ynear end -of the antenna toward the vdiis- Vtantend, thereby producing an antenna structure having relatively lowimpedance vfrom .theVV near end,

andy high impedance characteristics when 1 viewed from the distant end.With such an antenna, the distant end is left open, less irregularitywill be introduced at the nearV end,`to' wliich the terminal circuitslare connected-than with ,an antenna in which the 'loading is uniformlyldistributed or uniform-v ly`lumpedl throughout its length. Such anantenna will therefore have substantially constant'impedancetocorrespond to the impedancefof al'plurality of individual selectingcircuits :that may be connected to it for e multiplex operation.

Connected withfthe ilters F1, lF3 are thecircuits havingV associatedtherewith vrcceiving ,apparatus designated R1, R2', R,s re- ;spectively.Since the filters are in series, it V.is desirable, for eiiicientoperation, that each :offt-he. lters shall. offer a. minimum imped-Vance to. allfr'equencies outside the range that 7 they are designed` totransmit to their re- 4.,. spective receiving-` apparatus.

clear by Fig. la,

This is made which shows vthe impedf ance-frequency characteristicV ofsuch .group of iilters. j Filter F1, which isdesignedto transmit tothereceiving apparatus R, a

, band of `frequencies lying between 7] and/f2,

i' will have an impedance Z for all frequencies` lying between 1 and/2,but will have substantially less impedance for the frequencies outsidethis range. The vfilter F2, which transmitsthe band :of frequenciesbetween impedance respectivev f3 and fMpand the -filter the bandbetweenf5 andfs, likewise. have an Z for all frequencies within their bands,.but Lsubstantially no impedance ,for the frequencies outside theirband.

y Vmeans o-f a tapered 4loaded antenna having a broad bandcharacteristic such Vwith aplurality teristics shown 'shownin Fig. 2.rangement shown Y as to transmit readily-frequencieslying between f1 andfwand having connected thereof .filters having lthe charac-l in Fig. la,it ispos'sible to effect multiplex operation with theminimum of loss issignalingetticiency. i VAnother form of tapered loaded filter is Itdiffers from the arin Fig. l `in-vthat the. inductances 2f, 3', 4 and 5aregspaced along theantenna Yl atV equal intervals. These in ductances,however, are not equal in magni F3, 1 which transmits tude, but are,`designed to have increasingly greater magnitudes in the direction fromthe near end of thevantenna toward the distant end. This is shown in thedrawing byV an increasing number'of turns yor convolutions ofthesucceeding inducta-nces. rWVhile no definite rule 'can be laid down asto thefmagnitudes of succeeding inductances, is dependent upon theconstants of the an-Y tenna structure, it should be understoodl that theimpedance of*succeeding.-subnetworks, viz, combinations of theinductance with the uniformly distributed capacities represented Kshouldincrease uniformly in the direction from'th'eI near end toward thedistant end ofthe antenna, 'so' that such an antenna will` have4rel'a'tivelyvlow4 rimpedance when viewed from the nearend andrelative'- l high impedancewhen yviewed frointhe distant end. l i I Y,While antennae ymay be constructed inl accordance with the principles 1heretofore stated, which will tend to reduce their-regu'- since Vthis Ylarity of impedance existing between the open end of the antenna and theether, Vthis irregularitycannot be entirely eliminated in the structuresheretofore described. @It is accordingly desirable yto terminate atapered loaded antenna, such, Vfor example, as that shown in Fig. 1bymeans of a network which has the same impedance as `the char-Yacteristic impedance ofthe antenna which in this case would be thecharacteristic imped-l ance of the endsection. Such afinodeA oftermination is. shown in Fig. 3, inA which the distant end of theantennalis terminated through an impedance ZO, which v is pureresistance. This is truebecause theV characico teristic impedance v'of acircuit, consisting'of a long wire .to ground,

resistance with littlev or ponent Vwhen measuredv such as are usedinradio signaling. Sucha terminating network as the resistance Zojhas theeffect of prolonging'the'.tapered sor as to eliminatesharp'irregularitybetween the end of lthe antennay and the other,thereby reducing reflection losses. Y

A similarresistance,such as is shown in Fig. 4, may be used inconnection with the taperedk loadingof the type shown in Fig. 2. Theapplication of the foregoing principles to a. loop antenna is shown inFig. '5, in which the inductances l1, 12 andvl) of un` equal Vmagnitudeare. spaced at equal distances apart throughout the length of theantenna l0. The distant end of the antenna is terminated by a resistanceZ., equal tothe characteristic impedance at high 'frequency of theantenna.l Receiving apparatus may be coupled or otherwise `connectedwith :the antenna l0 in the manner Vshown in the iig-` ure. Althoughthis ligure'shows the appli- `cation thereto of the type of taperedloading n e for a parallelv pair of wires, has been found to bepractically -pure at; highV frequencies loadingV en ininating network,consisting of plicaloleV tov -l represents an' underground ing-receivingapparatus .RA near end thereof lminated' throughv i' may be applied tosuch type ofy antennae.

' Fig. 7 ,I have shown the parallel method ofy lf:v

Fig. 1.k InV this figure antenna connecting the terminal receivingcircuits with the antenna structure as an alternative form of the seriesarrangement shown in may have any type of tapered loading, and which mayor may not be terminated by the impedance Z0, has connected at thepoints 41 laplurality of branch circuits 42, 43 and 44 which 45, 46 andhave connected therewith band filters 47 respectively,

Y ends of which areLconnected the vacuum I tube devices 48, 49 and 50the impedance-frequency Y Y shown in ance with the principlesrespectively havingassociated"therewith the receivers 5l, 52 and 53respectively. The said filters have characteristics as Thus filter 45,which is designed to'transmit the band of frequencies lying between f1'and f2 willoer the minimum impedancefor frequencies lying within thisrange, and the maximum impedance for frequencies Without the range.VThese filters, it will beV seen, have a different impedance-frequency.characteristic from those shown'in Fig. l.

Fig.v 7a.

The arrangement shown in Fig. 8 ishan Y distances awayl tion ofthe saidterminal apparatus expansion of the idea disclosed in Fig. 7 to loopantenna structures.4

antenna 60, which may be d disclosed in Figs. 1 and 2, and may, ifdesired, be terminated through 'a resistance Z0, the terminals 6l aplurality of-branch terminalcircuits 62, 63 and: 64, which haveassociated therewith band filters 65, 66 and 67 having the impedancevfrequency characterimpedance f l' turn, are coupled to the receiversistics/shown in ig. 7a. These lters are Vcoupled by transformers 68, 69and 70 respectively with the balanced detecting devices '71, 72 and 7 3respectively, which, in

` 77, 7 8 and 79 respectively by means of the transformers 74, 7 5 and76 respectively.

It will accordingly 'be seen that my invention, as disclosed in theforegoing description and in the drawing, consists not only in theapplication oftaperedloading to an antenna structure, but also in thecombination of an antenna vof this type with a A.ter-

pure resistanceandsimulating electrically the surge of such yantennastructure.

Furthermore, my invention comprises the combinationof the foregoingelements to- -connected at the 40, which to the distant' In this figurethe. loaded in accord.vv

has'connected across gether with receiving zcircuitsconnected with ytheganteima structure. in such mannen asgto' affordi the ,minimum.impedance to current-s of. frequencies other,y than those lwhich arestood that it is capable of embodiment in y other and different formswithin the spirit.V a, y and scopeof the appended claims.

lThat is claimed is:l

Y `1. An antenna' having indiictancesv conl nected serially therein atpredetermine d so points, the dist-ance ,between successive in- -vductances diminishinginthe direction away from the point of alconnection of terminal apparatus with the said antenna. n 2. AnV antennahaving -inductances con.

nected "seriallyv therein atV predetermined points, the distancesbetween Lsuccessive inductances progression being in decreasing from thepoint-of ,connection of the terminal apparatus with the ysaid antenna. p

3. An'v Vantenna I nected serially therein at*l progressivelydegeometrical having inductances iconcreasing intervals along saidantenna in the directionaway from thepoint of connection' of theterminal apparatus with thesaid an- ,y

tenna.

v4. In afradioisignaling system,the combination with a loaded' antennaadapted forl f connectionwith terminal apparatus, the said antennahaving inductances connected sie-, rially therein at progressivelydecreasing from thejpoint :of connecsaid antennav and a resistancesimulating electrically the surge impedance of' thesaid with the ica' .y

loaded antenna at its operating'frequency connected across the normallyyopen .end of` the said antenna;v y v 5. In a radio signaling system,vthe oo mbination with a loadedantennahaving indnctancesconnectedserially therein at pro- 'gressively decreasing distances Afrom its nearendtoWard its distance yendofa resistance equal to the surge impedanceof the said antenna, connected betweenthe distant'end of the saidantenna and ground. f 6. In a'radio signaling system, the vcombinationwith a loaded 'antenna having in-` ductances connected serially thereinatpro-` gressively decreasing end toward its distance end and having itsdistant end lgrounded through a resistance equal to the surge impedance,of the said i a plurality of'terrninal circuits A connected with thenear end of vthesaid 'Y antenna, the connecting antenna, of

ila

distances from its ynear means beingsuch as f to offer minimumimpedanceA to currents of v frequencies other than those intended forthe, 1an

circuit ofthe particular connecting means.

' 7.' In a 'radio signaling System,jthe combination With a: taperedloededvantenna having a plurality of inductances iconnected seriallytherein,of a plurality of terminal cir- 5 cuits connected therewith bymeans of series lters, the said lters being so fdesigned'vas toolferfminimum impedance-'to al1-frequencies other than In testimonywhereof, Ifhztve signed name' to this specification this .29th day ofAugust, 1922. f :e l HERMANA. AFFEL.

